The present invention relates to a voltage generation circuit.
As a liquid crystal panel (electro-optical device) used for an electronic instrument such as a portable telephone, a simple matrix type liquid crystal panel and an active matrix type liquid crystal panel using a switching device such as a thin film transistor (hereinafter abbreviated as “TFT”) are known.
The simple matrix type liquid crystal panel allows power consumption to be easily reduced in comparison with the active matrix type liquid crystal panel. However, the simple matrix type liquid crystal panel has disadvantages in that it is difficult to increase the number of colors and to display a video image. The active matrix type liquid crystal panel is suitable for increasing the number of colors and displaying a video image. However, the active matrix type liquid crystal panel has a disadvantage in that it is difficult to reduce power consumption.
In recent years, an increase in the number of colors and a video image display have been demanded for a portable electronic instrument such as a portable telephone in order to provide a high-quality image. Therefore, the active matrix type liquid crystal panel has been increasingly used instead of the simple matrix type liquid crystal panel (JP-A-2003-22063).
In the active matrix type liquid crystal panel, it is desirable to provide an operational amplifier which functions as an output buffer in a data line driver circuit which drives data lines of the liquid crystal panel. Along with an increase in image quality, resolution, and the number of grayscales of a display panel, it is necessary to reduce power consumption of the data line driver circuit.